1. Field of the Invention
This invention relates generally to systems for recording and reproducing voice messages and particularly to such systems as adapted to communicate with a telephone network. The voice message storage system of the present invention is further adapted to record such messages in the form of digital data and to operate automatically for recording and reproducing voice messages under the control of digital computers included in the message storage system.
2. Description of the Prior Art
Digitized voice processing, a process in which an analog voice signal is converted into digital data, is frequently employed for long distance communications. When used for telecommunications, digitized voice signals may provide clearer sound and speech than analog voice transmission. This advantage is obtained because the information contained in a digitized voice signal may be more easily preserved during transmission than the same information transmitted in analog form. Consequently, digitized voice transmission is used for virtually all satellite communications. Presently, telecommunication companies are proceeding to convert their long distance transmission facilities to utilize digitized voice signals. It appears that digitized voice transmission is becoming the standard of the communications industry and will soon become the foundation of nationwide and worldwide communication networks.
Digitized voice recording is a further technique in which the digitized voice signal rather than the corresponding analog signal is recorded with some suitable digital data recording apparatus. Reproduction of such a recorded digitized voice data is accomplished by reversing the digitization process, that is, by converting the stored digital signal back into an analog electrical signal. The sound reproduction quality of digitized voice recording is equivalent to, and may even be better than conventional analog recording. Presently, digitized voice recording and reproduction is being used in certain limited, dedicated applications such as in telephone systems to transmit special purposes announcements, in aircraft to provide cockpit warning messages, in schools as an audio learning aid, and in the phonograph record industry to provide higher fidelity master recordings. One characteristic common to these present applications of digitized voice recording is that they all employ a specialized apparatus dedicated to the particular application for recording and reproducing the digitized voice signal.
Similarly, specially adapted devices, generally based upon conventional, analog magnetic tape recording technology, are widely available for recording and reproducing telephone messages. While such telephone answering machines are readily available and are moderately priced, they are highly specialized in that they generally are capable of transmitting only a single, standard, pre-recorded message at the beginning of a telephone call and then optionally recording a message from the caller. Further, a time limit is frequently imposed on the length of the caller's message, thus restricting its content. Additionally, if a sequence of callers leave a series of individual messages, those messages must generally be reproduced in the order in which they were received irrespective of the caller's identity and also irrespective of the message's urgency.
The inflexibility of current automatic telephone answering machines has allowed the coexistence and even the simultaneous emergence of a wide variety of different telephone answering services. Some such answering services are as informal as a spouse or a relative taking a message when the intended recipient is unable to answer the phone. Similar informal and formal telephone answering services exist in the business community where secretaries, switchboard operators, hotel personnel, commercial answering services and radio paging service companies routinely accept telephone messages for subsequent retransmission to their intended recipient.
However, all of the preceding answering services, both informal and formal, are relatively ineffective in actually transmitting essential information due to natural constraints on the message-taker and the highly specialized information included in most business messages. Business messages, because they normally include "shop talk," may be perfectly clear to the intended recipient but are generally gibberish to those unfamiliar with the particular vocabulary. Thus, such telephone messages are generally limited to five to six (5-6) words per message. A significant percentage of messages consist only of "please call so-and-so," or "so-and-so called, will call back." Such messages communicate little information, are relatively expensive to capture and forward, inefficiently use the message-taker's time, frequently are the source of much frustration, and may result in the loss of business opportunities. It has also been observed that present telephone message systems frequently produce a sequence of events sometimes referred to as "telephone tag" in which pairs of individuals, in attempting to communicate, respectively leave and receive a sequence of messages indicating that they are attempting to communicate. Further, present message systems frequently lose or misinterpret the urgency or emphasis of a message due to the message-taker who impersonalizes, abbreviates, and/or editorializes the message and who is also unable to reproduce the voice inflection of the caller.
The difficulties and inadequacies of the present telephone message forwarding systems identified above may be greatly exacerbated when individuals in different time zones attempt to communicate. Time zone differences reduce the interval during which both individuals are simultaneously available to communicate. Consequently, for such individuals, the possibility that an attempted communication will be unsuccessful increases. Time zone differences also produce periods of peak message traffic which may swamp message taking services and thus result in long hold periods or busy signals even in situations where no messages exist. Further, individuals separated by such distances are more likely to incur excessive long distance telephone charges, particularly if their attempt to communicate results in "telephone tag."
Beyond the generalized need for effective telephone answering and message taking services existing throughout all business enterprises, certain types of businesses depend vitally upon effective telephone communications for their daily operation. Such enterprises are generally characterized by geographically dispersed facilities and/or employees and by a need to coordinate activities of the various facilities for the enterprise's successful operation. A prime example of such an enterprise is the airline industry. Airlines, for example, must make and receive thousands of telephone calls at specified times each day for pilot and flight attendant sheduling. Further, airlines also receive and must respond to numerous telephone calls from customers requesting flight information. A corresponding need to distribute information exists in supermarket grocery chains and similar enterprises which must routinely communicate price changes thoughout the organization. A final example similar to that of the airline industry exists in the public service sector wherein school districts must regularly identify and schedule substitute teachers. In a moderately sized urban school district, substitute teacher scheduling may require placing one-thousand (1,000) telephone calls per day to complete the scheduling of approximately two-hundred (200) substitute teachers. In each of the foregoing examples, timely and effective communication of information via the telephone system is vital to the successful operation of the respective organizations.
Even in enterprises which are not vitally dependent upon prompt, effective use of the telephone system for their successful operation, spoken messages are generally preferable for the vast majority of communications. Indisputable proof of this preference is established by the fact that the telephone system's peak utilization and highest billing rate occurs during the hours of normal business operation. The use of telecommunications by businesses in preference to other means is readily understandable since voice communication is faster, cheaper, and generally more effective than communication by written documents. Voice communication is generally faster because it avoids the time delay associated with the preparation and delivery of written documents. It is also generally cheaper overall because it avoids relatively expensive intermediate step of document preparation and the subsequent need for document storage. Finally, voice communication is generally more effective because it communicates the actual voice, tone, and urgency of the individual speaker.
In addition to the traditional telephone answering services totally staffed and operated by humans, several identifiably distinct approaches for providing such a service employing varying degrees of automation have emerged in response to the business community's general need for timely and effective telecommunications. Such systems may be grouped into paging-oriented systems, PABX-oriented systems, and network-oriented service systems. In paging-oriented systems, a short message, usually ten (10) to thirty (30) seconds long, is recorded, its intended recipients are then notified via a radio receiver which they wear continually that there is a message waiting for them, and then the recipient must place a return telephone call to receive the previously recorded message. PABX-oriented systems represent a more recent development than paging-oriented systems. Such systems integrate a message storage device for recording and reproducing telephone messages directly into PABX telephone equipment. While such PABX-systems may provide operational facilities and features beyond those available in the familiar analog tape recording telephone answering machine, they are financially practical only for large economic enterprises which can individually justify the installation of a PABX. Further, current PABX systems lack the flexibility and capacity needed to provide a generalized service capable of responding to various differing requirements for timely and effective telecommunications at an economically acceptable cost. Lastly, the present available network-oriented system requires a relatively expensive operator who must mediate the capture of each message and its subsequent retransmission to its intended recipient.